At the present time, the generally accepted method of curing bellies and other meat products is to inject the product, through a series of needles, with a pickle or curing solution, and then curing the product in a smokehouse. It is extremely desirable that a controlled amount of fluid be injected into the product, and the desired amount or percentage will vary according to several factors.
In applicant's earlier device disclosed in U.S. Pat. No. 3,863,556, a machine was disclosed for injecting fluid into the meat products which attempted to sense the thickness of the products and to inject a corresponding amount of injector fluid thereinto. In the injector of said patent, the amount of injection is determined by the length of time the control valve is open and the time that the control valve is open is determined by the thickness of the belly or product. In applicant's earlier device a stripper bar moves downwardly and rests on the surface of the product, and the average height of the stripper bar determines the amount of time that the flow valve is open. A cam arrangement was used in applicant's earlier device to control the valve opening time as desired based on the thickness of the belly and also on other factors such as the bleed characteristic of a thick belly as compared to a thin belly. As stated, the amount of injection in applicant's earlier machine is dependent on the time that the flow valve is open. This time factor will not vary in exact proportion to the thickness of the belly because of the crank action which moves the fluid manifold and needles upwardly and downwardly. In other words, when a crank is at the bottom of its stroke, the needles would be in a half-inch of belly much longer than they would be in a half-inch of belly at the middle of the stroke. Therefore, the timing of the valve opening becomes a complicated matter and the control cam becomes extremely difficult to establish.
It is impractical to move the needles at a constant velocity into a meat product. Thus, it is common in the art to utilize a cam or crank whereby the needles are moved into and out of the meat product with a crank action. This means that the velocity of the needles varies throughout the penetration and retraction strokes. The velocity of the needles starts from zero at the top of the penetration stroke, moves to maximum velocity halfway through the penetration stroke, and slows to zero velocity as maximum penetration is reached, and the retraction stroke commences. The retraction stroke duplicates the velocity curve of the penetration stroke.
Since the velocity of a crank-activated gang of needles varies, a continuous fluid supply pump will provide a varying amount of fluid in different stratas of the meat product. The stratas through which the needles most quickly pass will receive the least fluid, and the stratas through which the needles more slowly pass will receive more fluid. This violates the ultimate objective of uniformly distributing the fluid through the thickness of the meat product. The device and method of this invention overcome this problem by varying the amount of fluid delivered through the needles in proportion to the varying velocity of the needles as they move into and out of the meat product.
Therefore, it is a principal object of the invention to provide an improved machine and method for injecting fluids into meat products wherein the flow of fluid through the injection needles is at a rate proportional to the velocity of the needles.
A still further object of the invention is to provide an injector machine employing displacement pumps which are driven from the same crank which drives the fluid manifold upwardly and downwardly or at least from another means which moves in conjunction with the fluid manifold.
A still further object of the invention is to provide a machine for injecting fluid into meat products wherein a stripper plate senses the surface of the meat product and the stripper plate controls the displacement of a displacement pump in accordance with the thickness of the meat product.
A still further object of the invention is to provide a machine for injecting fluid into meat products or the like which has eliminated the need for controlling the time that the flow valve is open.
A still further object of the invention is to provide a machine for injecting fluid into meat products or the like which is economical to manufacture and durable in use.